Electronic sound distribution system

ABSTRACT

A sound distribution system for giving the effect of physical dimensions to sound by sequentially and cyclically distributing the sound input signal among a plurality of output channels to which are connected corresponding speakers located along the perimeter of a listening area. The sound distribution system comprises an electronic apparatus that sequentially ungrounds the speakers by sequentially turning off gates that are connected between ground and the output channels. The gates are sequentially turned off by a plurality of trains of switching signals that are phased apart so as to present the individual switching signals to the gates in sequence.

[4 Mar. 25, 1975 1 ELECTRONIC SOUND DISTRIBUTION SYSTEM [75] Inventor:Gary L. Wedan, Duluth, Minn.

[73] Assignee: Robert Urbick, Duluth, Minn. a

part interest 22 Filed: May 24,1972

[21] Appl. NO.Z 256,516

[52] US. Cl...... 179/1 GQ, 179/1 G, l79/l00.4 ST,

179/100.l TD [51] Int. Cl. H04r 5/00 [58] Field of Search 84/D1G. l,DIG. 27; 179/1 G, 1 GP, 1 GQ, 100.1 TD

[56] References Cited UNITED STATES PATENTS 2,114,680 4/1938 Goldsmith179/1 GP 2,792,449 5/1957 Bottini l79/l00,l TD 2,832,829 4/1958Reynolds... 179]] GP 2,927,963 3/1960 Jordan 179/1001 TD 2,931,8624/1960 Vermeulen et a1. 84/DlG. 1 2,941,044 6/1960 Volkmann 84/D1G. 13,018,335 l/l962 De Rosa 179/1 G 3,272,906 9/1966 De Vries.....3,374,315 3/1968 Gladwin 179/1 G 3,375,329 3/1968 Prouty l79/l00.l TD3,586,783 6/1971 Brickner.. l79/l GQ 3,654,394 4/1972 Gordon 179/15 BL3,665,105 5/1972 Chowning 179/1 J 3,684,835 8/1972 Orban 179/1 GP3,757,046 9/1973 Williams l79/l GQ Primary Examiner-Kathleen H. ClaffyAssistant Examiner-Thomas DAmico Attorney, Agent, or Firm-Larson, Taylor& Hinds [57] ABSTRACT A sound distribution system for giving the effectof physical dimensions to sound by sequentially and cyclicallydistributing the sound input signal among a plurality of output channelsto which are connected corresponding speakers located along theperimeter of a listening area. The sound distribution system comprisesan electronic apparatus that sequentially ungrounds the speakers bysequentially turning ollgates that are connected between ground and theoutput channels. The gates are sequentially turned off by a plurality oftrains of switching signals that are phased apart so as to present theindividual switching signals to the gates. in sequence.

18 Claims, 7 Drawing Figures PAIENIEDMRZS 197s sum 2 or 4 3 mm we 1 iT/zfllll MENTEUMRZS i975 SPEAKER '0 I I l I snmaurq XPEAKER "A" SPEAKERB" I I90 SYNC l 7 g OUT o scum) DIST 3 (I76 SYSTEM [4 A AMP. s CHANNEUA"*1 l rlfil M 1?? |ss smc sgg z B I 4 AMP, CHANNEL B souuo DISTESSYSTEM#24 c R 1AMP. CHANNEL 0 *1 :79 I85 smc i D W CHANNEL D scum) DIST3SYSTEM#34 FIG. 6

W'EMEUH z a sum u q PHASE H 13 ROTATION 2nd ROTATION 1 3rd ROTATIONELECTRONIC SOUND DISTRIBUTION SYSTEM BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to an electronic systemfor c'yclically distributing an input sound among a plurality ofspeakers to thereby give the sound as heard by a listener addeddimensions of form, motion and space.

2. Description of the Prior Art The concept of selectively distributingsound to variously located speakers is, of course, conventional. Anearly system employing this concent was used to create a stereo effectfrom a monoaural recording. Reference is made to a U.S. patent toPalladino', U.S. Pat. No. 3,219,759 which discloses a system using twospeaker channels and an electronic circuit for splitting the phase of amonoaural sound input and for delaying one of the channels by an amountthat varies in a non-linear manner with the frequency.

Other patents have discussed the use of a plurality of speakers tosimulate a large-area sound source as opposed to a point source thatresults from the use of only one speaker. In U.S. Pat. No. 2,114,680 toGoldsmith, one embodiment of the invention employs a plurality ofspeakers connected in parallel to a sound input signal throughcorresponding amplifying tubes. Superimposed on the grids of the tubesare auxiliary alternating voltages that have a phase difference suchthat when one tube is conducting at a maximum, the other tubes are at aminimum, and the source of the sound effect shifts from speaker tospeaker at a frequency equal to that of the applied alternating gridvoltage. A U.S. patent to Reynolds, U.S. Pat. No. 2,832,829 discloses amechanical system for achieving sound distribution. The system rotates acircular ring through a plurality of equally spaced coils each coilbeing connected between ground and a corresponding speaker. The ring isbasically formed from a dielectric material, but an arcuate sector ofthe ring is made up of an iron slug so that when the slug passes throughthe coil, the speaker is grounded. Systems like those disclosed in thesetwo patents have a number of disadvantages. For example, switching noiseis induced into the speakers when the switching between speakers occurs.Further, such systems provide very poor control over the switching frequency. Mechanical systems suffer obvious disadvantages regarding wear,reliability, cost, size and weight.

SUMMARY OF THE INVENTION According to the present invention, acompletely electronic sound distribution system is provided whichcyclically distributes an input sound signal among a plurality ofspeakers. The cycle or switching frequency among the speakers is botheasily adjustable in' small increments and continually adjustable over acontinuous range of frequencies. In addition, the system of theinvention is such that no perceptible switching noise is picked up bythe speakers.

The preferred embodiment of the invention employs four speakers whichare normally grounded through a switchable gate. A plurality ofswitching signals are generated for sequentially turning off the gates,thereby sequentially ungrounding the speakers'and permitting thecorresponding ungrounded speaker to respond to a sound input signalwhich is coupled in parallel to all the speakers.

A system in accordance with this embodiment of the inventionaccomplishes the desired sound distribution through the provision of acoupling network for coupling the sound input signal to the system inparallel to a plurality of speakers. Each of a plurality of signalresponsive electronic switching devices, equal in number to the numberof speakers, selectively grounds a corresponding speaker, each speakerwhen ungrounded, being responsive to the sound input signal. A pluralityof trains of switching signals are generated which are equal in numberto the number of speakers, and which differ in phase so that switchingsignals or pulses are presented sequentially to corresponding switchingdevices and hence that the switching signals sequentially actuate thecorresponding switching devices thereby producing a cyclic distributionof the sound input signal to the speakers.

Other features and advantages of the present invention will be set forthin or apparent from the detailed description of the preferred embodimentof the invention found hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram ofone embodiment of the invention;

FIG. 2 is a detailed schematic circuit diagram of the embodiment of theinvention shown in FIG. 1;

FIG. 3 is a graph of the voltage wave forms at various points in thecircuit of FIG. 2;

FIG. 4 is a plan view of a schematic representation of travelling soundwaves produced by the speakers of the system of the invention withdifferent parameters held constant;

FIG. 5 is a graphical representation, in polar coordinates, of the waveforms of several musical sounds;

FIG. 6 is a schematic block diagram of a system combining threesynchronized embodiments of the invention;

FIG. 7 is a graph of the voltage wave forms which are presentedsequentially to corresponding switching devices.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although the structure andoperation of the invention will be described with respect to a presentlypreferred embodiment of the invention, it will, of course, be understoodthat the particular values of the components given are merelyillustrative and that these values may, of course, be varied withoutdeparting from the scope of the invention.

Referring to FIG. 1, a block diagram of a system in accordance with apresently preferred embodiment of the invention includes a highimpedance terminal 11 and a low impedance terminal J2 for receiving thesound input signals. A preamplifier l3, connected to terminals 11 andJ2, amplifies the input signal and is, in turn, connected in parallel toa plurality of signal responsive switch means, such as electronic gates16, 17, 18 and 19. Gates I6, 17, 18 and 19 either pass the input signalto respective outputs, such as output terminals JA, 18, JC and JD, orground the input signal, at respective grounds indicated at 26, 27, 28and 29, depending upon the presence or absence of a switching signal atthe respective gate. Alternatively, the input signal can be directlycoupled to gates l6, l7, l8 and 19 by bypassing preamplifier 13 throughan auxiliary input output terminal J8.

Four signal trains of switching signals, one signal train correspondingto each of the four gates l6, l7, l8 and 19 and consequently to each ofthe four output terminals JA, JB, JC, and JD are generated by furthercircuitry, the signal trains differing in phase such that the switchingsignals from the individual signal trains are presented sequentially togates 16, 17, 18 and 19. More specifically, an oscillator 40 generates atrain of timed pulses which are delivered, through a switch S4, when thecontact arm of switch S4 is positioned at a first terminal denoted 41,to a transistor driver circuit 42. Transistor driver 42 amplifies thepulses which are then applied, through a switch S2, to a first frequencydivider network 45 when the contact arm of switch S2 contacts a firstterminal 43, i.e., with switch S2 in position 43, or to a secondfrequency divider network 49 with switch S2 in the second positionthereof, in contact with terminal 47. With switch S2 in the firstposition thereof, divider 45 divides the frequency of the train ofpulses generated by oscillator 40 in half. The train of pulses is thentransmitted to divider 49 which further divides the frequency in half bygenerating, from alternate pulses in the train, first and secondsubtrains of timed pulses. The first sub-train of pulses is applied tosquare wave generator 50 whereas the second sub-train of pulses isapplied to a square wave generator 51. The first pulse from divider 49is applied to square wave generator 50, which in turn transmits a squarewave switching signal from a first output thereof to a first controller53. The next pulse from divider 49 is applied to square wave generator51 which transmits a square wave switching signal from a first outputthereof to a second controller 56. Similarly, the third pulse fromdivider 49 is applied to square wave generator 50 which transmits asquare wave switching signal from the second output thereof to a thirdcontroller 54, while the fourth pulse from divider 49 is applied tosquare wave generator 51 which transmits a square wave switching signalfrom the second output thereof to a fourth controller 57. Hence, thefirst four input pulses to divider network 49 are squared up by squarewave generators 50 and 51 and applied to separate controllers 53, 56, 54and 57.

Controllers 53, 56, 54 and 57 are individually coupled to, and controlswitching of, gates l6, 17, 18 and 19, respectively. Because eachcontroller is actuated by a train of switching signals which differs inphase from the switching signals in the other trains, controllers 53,56, 54 and 57, in turn, sequentially actuate the corresponding gates l6,17, 18 and 19 to thereby produce a revolving or cyclic distribution ofthe input signals to the output terminals JA, JB, JC, and JD. Thus, toreview the system so far described, a trainof timed pulses is used togenerate four trains of square wave switching signals, which differ inphase from one another and which produce the cyclic distribution of thesound input discussed herein above. Although the. preferred embodimentuses four speakers, the invention is not to be limited to this number.

It may also be desirable to connect a number of individual sounddistributions systems in parallel, such as is shown in FIG. 6. This canbe accomplished by switching switch S4 from position 41 to position 60,thereby disconnecting oscillator 40 from the circuit and connecting in asynchronizingpulse inputreceived at a sync" input terminal J5. Asynchronizing output signal can be transferred to other sounddistribution sys tems through a further sync output terminal J4 that istapped off at the input to controller 53 from the switching signalgenerated by square wave generator 50.

In addition, switch S2 may be used in selective ones of the parallelconnected sound distribution systems to provide a different frequency ofcyclic distribution of the input signals, i.e., a frequency of eitherone-half or double the frequency of the non-selected sound distri butionsystems.

The cycle frequency can be defined as either the number of times any onegate is turned on per second or as the number of revolutions among thefour outputs that the input signal makes per second. This cyclefrequency can be varied by a manual frequency control input 65 connectedto oscillator 40 through a switch S3 which is in the first position incontact with a first terminal 66. Alternatively, with switch S3 in thesecond position thereof in contact with a second terminal 68, a footpedal controlled input 69 is connected to oscillator 40 to control thefrequency thereof. Both foot pedal frequency control input 69 or manualfrequency control input 65 can be variably adjusted to provide avariable output frequency thereby varying the cycle frequency, or can becontinually adjusted to provide a varying output frequency, therebyproducing a varying timed relationship between switching signals in thesame cycle in addition to producing a variable output frequency betweencycles. The cycle frequency can be monitored through a scanner 70 havinga visual indication 71, which blinks once per cycle corresponding toeach time a switching signal from square wave generator 50 actuatescontroller 54.

Referring to FIG. 2, there is shown a schematic circuit diagram of theblock diagram of FIG. 1. Although the circuit will be described only ingeneral terms and reference will be made only to major components, allcomponents are identified to that respectative values thereof can beobtained by reference to the list of components found hereinbelow. Whereapplicable, like components in FIGS. 1 and 2 are designated by likeidentifying symbols. I

As desired, high impedance and low impedance sound inputs are providedat input terminals J1 and J2, respectively. An electrical ground G1,corresponding to individual grounds 26, 27, 28 and 29 in FIG. 1, isconnected to terminal J2 through ground line or bus 201 and a resistorR35. The high impedance input terminal J1 is connected through aconductor 202 to the pre-amplifier referred to above which includes acoupling capacitor C56 and first and second field effect transistors(FETS) T1 and T2. The output of this preamplifier which taken at thecollector of transistor T2 is connected through a gain control resistorR60 and input line 204 to output terminals JA, JB, JC, and JD.Alternatively, as mentioned above, the pre-amplifier can be bypassed andthe input signal can be directly coupled to the outputs throughauxiliary terminal J8 and an isolation resistor R20. Output terminalsJA, JD, JC and JDiare connected in parallel to input line 204 throughrespective isolation resistors R21, R22, R23, and R24 and couplingcapacitors C31 and C41, C32 and C42, C33 and C43, and C34 and C44. Theother line 201.

' sistors have both a high input impedance and a high output impedance,thereby minimizing the amount of switching noise induced into thecorresponding output terminal and use a very small signal at the gate tocontrol a very large signal through the transistor, further tending tominimize induced switching noise.

As described hereinabove, the signal trains of switching signals aredeveloped from a single train of timed pulses by a plurality ofsuccessive stages. The train of timed pulses is generated in oscillator40 that includes transistors T3 and T4 in a conventional astablemultivibrator circuit. Also as described, the frequency of the outputsignal of oscillator 40 can be varied manually or with a foot pedalcontrol, and, more specifically, is in part determined by the resistanceof a manually controlled resistor R10A or by the resistance of a footpedal controlled resistor R10B, depending on the position of switch J3.

The output of oscillator 40 is connected through switch S4, in the firstposition thereof, through coupling capacitor CS1 to the transistordriver 42 which was referred to above and which includes cascadedtransistors T and T6. Alternatively, the input to driver 42 can be takenthrough sync input terminal J5 if switch S4 is the second positionthereof. The driver output, which is an amplified train of timed pulses,is connected through switch S2 to a network of four bistablemultivibrators or flip-flops FFl, FF2, FF3 and FF4 which are formed bytransistors T to T17 and resistor packs RPl, RP2, RP3 and RP4.

Flip-flops FH and FF2 are used as frequency dividers and flip-flops FF3and FF4 are used as square wave generators. With switch S2 in theterminal 47 contact position flip-flop FFl is bypassed and the outputfrom driver 42 triggers flip-flop FF2. with switch S2 in the terminal 43position, the output from driver 42 is applied to flip-flop FFl whichdivides the frequency of the signal by half. The signal from therighthand output of flip-flop FFI is applied to flip-flop FF2 throughcoupling capacitor C53. As is well known in the art, provision can bemade for taking the output of a flipflop at either side of the flip-flopcircuitry and, at any one time, one side of the flip-flop will be in ahigh state while the other side will be in a low state. Thus a singleinput signal can generate two output signals that are exactly 180 out ofphase. In this manner, the right-hand output of flip-flop FFZ is appliedthrough coupling capacitor C55 to flip-flop FF3 and the left-hand outputof flip'flop FF2 is applied through coupling capacitor CS4 to flip-flopFF4. The right-hand and left-hand output from flip-flop FF3 isrespectively taken by conductor 211 and conductor 213 and the right-handand lefthand outputs from flip-flop FF4 are respectively taken byconductor 212 and conductor 214.

Controllers 53, 54 56 and 57 shown in FIG. 1 are identical and include,respectively, switching transistors T21, T22, T23 and T24 shown in FIG.2. Only the circuit components connected to switching transistors 21will be described in detail with reference to FIG. 2, the circuitcomponents connected to the other switching transistors being identical.Corresponding circuit components connected to the switching transistorsare identified with the same numeral in the tens position of theidentifying symbol, and all circuit components connected to the sameswitching transistor are identitied with the same numeral in the onesposition" of the identifying symbol. Switching transistor 21'!" is annpn transistor having a collector 301, an emitter 302 and a base or gate303. Emitter 302 is connected to the gate of gating transistor T31through an output resistor R41 and a shaping capacitor C11 is connectedacross collector 301 and emitter 302. Connected to gate 303 is theparallel combination of a shaping capacitor C21 and a control signalinput resistor, or control resistor R31. A wave shaping integrationnetwork is connected between ground line 201 and the junction betweenoutput resistor R41 and gating transistor T31 and comprises a resistorR51 and a capacitor C61 connected in parallel. A positive signalappearing at a control resistor R31 turns on switching transistor T21which, when conducting, provide a low impedance path between collector301 and the emitter 302, thus passing any signal appearing at thecollector to the gate of gating transistor T31.

Scanning network includes cascaded transistor T7 and T8 and a light B2connected at terminals J6. The input to scanning network 70 is takenfrom the lefthand output of flip-flop FF3 through a resistor R25.

The power supply for the circuit is a standard DC power supplycomprising an AC input connected through a power control switch S1, apower indicating light B1, a step-down transformer Trl, a full waverectifier comprised of diodes D1 and D2, and a wave shaping filtercomprised of capacitor C1 and C2 and resistor R16.

The flip-flops FFl through FF4 function so as to produce four out ofphase trains of square wave switching signals from a single train oftimed pulses, each switching signal being a half cycle (180) in durationand differing in phase by a quarter cycle or from the correspondingsignal from the preceding signal train. For simplification, it isassumed that switch S2 is in the terminal 47 position, thereby bypassingthe flip-flop PH and effecting a doubling of the frequency that wouldhave resulted had flip-flop FFl been in the circuit. The first pulsefrom the driver changes the output from the right-hand output offlip-flop FF2 to, for example, the high state and the left-hand outputto the low state. Coupling capacitors C55 and C54 respectivelydifferentiate these two square wave signals producing, respectively, afirst signal that triggers flip-flop FF3 and a second signal which istransmitted to but does not change thestate of flip-flop FF4. Thetriggering of flipflop FF3 produces, for example, a high state squarewave switching signal from the right-hand output that is transmitted byconductor 211 to collector 301 of switching transistor T21, to shapingcapacitor C23 at the base of switching transistor T23, and to thecontrol resistor R34 connected to the base of switching transistor T24.If this switching signal isi arbitrarily designated the first switchingsignal and switching transistor T21 is the first controller, it can beseen that the switching signal is distributed to the first, third andfourth switching transistors (i.e., T21, T23 and T24) which correspondto the first, third and fourth controllers (i.e., controllers 53, 54 and57) in FIG. 1.

The next pulse from driver 42 switches the states of flip-flop FFZ suchthat the left-hand output is at a high state and the right-hand outputis at a low state. The high state output is differentiated by couplingcapacitor C54 and is applied to flip-flop FF4 to cause triggeringthereof and the low output is differentiated by coupling capacitor C55and results in a second signal which is applied to but does not changethe state of, flip-flop FF3. Thus, whereas the state of flip-flop FF3 isnot affected by the second pulse from the driver. this second pulse willchange the states of the outputs of flip-flop FF4. For example, theright-hand output of flip-flop FF4 is switched to a high state and theleft-hand output to alow state. Connector 212 transmits the right-handoutput of flip-flop FF4 as a square wave switching signal to thecollector of switching transistor T22, shaping capacitor C24 ofswitching transistor T24 and control resistor R31 of controller 53(i.e., to the second, fourth and first controllers). Switchingtransistor T21, normally in the offstate, did not transmit the firstswitching signal from the RP3 flip-flop to the gate of gating transistorT31 the instant it was transmitted thereto. However, as soon as thesecond switching signal, generated as a square wave switching signalfrom the right-hand output of flip-flop FF4, is transmitted, 90 later inthe cycle to control resistor R31, switching transistor T21 is turned onand the first pulse that was earlier applied to collector 301 is nowtransmitted through switching transistor T21 to the gate of gatingtransistor T31. Due to the effects of capacitor C11 and the parallelcombination of resistor R51 and capacitor C61, the square wave switchingsignal is given a rounded leading edge and a lengthened trailing edge,thereby reducing the switching noise induced in output terminal JA. andgradually turning off gating transistor T31, as explained below. Thus,the width or time duration of the square wave switching signal, asgenerated, is decreased by chopping off the leading portion of thesignal an amount equal to the time lag or phase difference between thesequential generation of the square wave switching signals.

Gating transistor T31 is normally conducting and thus the input signalto output terminal IA is grounded. However, when the first switchingsignal is applied to the gate of gating transistor T31, transistor T31is back biassed and gradually turned off, thereby gradually increasingthe amplitude of the input signal transmitted to the outputterminal JA.7,

In a similar manner, the third pulse from driver 42 is applied toflip-flop FF2, which again changes its states, the positive pulse fromthe right-hand output being applied to and triggering flip-flop FF3. Thestates of the flip-flop FF3 are then changed and a square wave switchingsignal appears at the left-hand output which is coupled, throughconnector 213 and capacitor C21, to control resistor R32, turning onswitching transistor T22, and to the collector of switching transistorT23 as a square wave switching signal. The square wave switching signalat transistor T21 now disappears and the trailing edge of the squarewave that is applied to gating transistor T31, as shown in FIG. &, isrounded off by capacitor C21 and the parallel combination of R51 andC61. Thus, the amplitude of the input signal transmitted to outputterminal IA is gradually decreased thereby permitting a mementary,simultaneous presentation of the input signals to output terminals JAand J B.

Referring to FIG. 3, the square wave switching signals are shown as theywould appear at the output of the respective controllers 53, S6, 54 and57. if there were no rounding of the square wave. Rounded square waveswitching signals are shown in FIG. 7 as they appear at the input to thegates of gating transistors T31 to T34 At 0 and time zero, no switchingsignal has been produced. later the first square wave switching signaland the train of signals B1 appears at the output of controller 53,FIG. 1. Then the square wave switching signals B2, B3 and B4sequentially appear at the outputs of, respectively, controller 56, 54and 57, FIG. 1, at times of 180, 270 and 360 in the first cycle,respectively.

Thus, with reference to FIG. 1, as was described in somewhat differentterms hereinabove, the first square wave switching signal generated bythe first pulse from driver 42 is delayed for approximately 90 beforebeing applied to gate 16 because controller 53 has not been turned on.The second square wave switching signal turns on controller 53 andallows the remaining approximately 90 of the first square wave switchingsignal to pass through to gradually turn off gate 16 thereby ungroundingoutput terminal JA. Each square wave switching signal is consequentlydelayed for approximately 90 at the respective controller before thecontroller is turned on by the next subsequent square wave switchingsignal. The net result of the switching signal circuitry is thatdescribed above, i.e., the sequential turningoff of the gates, causing asequential ungrounding of the output terminals and a resultantrotational or cyclic distribution of the input signal among the outputterminals.

Referring to FIG. 4, the rotational or cyclical sound distribution ofthree different types of signals among four speakers A, B, C and D isshown schematically. FIG. 4 illustrates that through a change in therotational speed of the signal, such as provided by adjustment ofresistor R10A or R108 of FIG. 2, and/or an independent change in theinput signal amplitude, and/or a change in the input signal timing, theeffects of motion or movement, form and musical structure can be sensedby a listener located in a listening area 155, the perimeter of which isdefined by the location of speakers A, B, C and D. More specifically,path indicates the motional effect produced by a continuous signalwithout a change in the signal amplitude. Path 152 indicates the effectproduced by a broken signal or one intermittently applied to the inputof the sound distribution system, the amplitude of the signal stillremaining constant. Path 154 indicates the effect created by a signalhaving both changes in amplitude and in the rotational speed. Thechanges in the amplitude of the signal move the signal in and out fromthe center 156 of listening area 155.

The examples of sounds that can create the signal paths depicted in FIG.4 are shown in FIG. 5. In the FIG. 5 graph, is equivalent to one measureof musical time notation and exemplary sound levels are indicated byconcentric circles 100 of decreasing amplitude in decibels (db). Waveform 111 is a constant low frequency square wave sound signal changing15db in amplitude every six cycles, four equal times every half measure.If gain control resistor R60 in FIG. 2 were set at the 15db level, thelow amplitude signal, denoted 113, FIG. 5 would be attenuated andonlythe spikes, denoted 114, would be audible at the speakers. Further,if the rotational distribution rate among speakers were set equal to themusical timing, the result would be similar to that illustrated by path152 in FIG. 4. The dimension of distance or space can be obtained withthe same signal by increasing the gain of the signal and rendering thelow amplitude part 113 audible.

Other forms" of musical sounds are depicted at 120 and 125 in FIG. 5.Form 120 is a pulsed mid-frequency half note that is centered about the20db gain and form 125 is a sharp sixteenth note that can be obtained,for example, from the pluck of a guitar string. It will be appreciatedthat by systematically varying the resistances of resistors RIOB or RNAin FIG. 2, the sound distribution of a musical score can be given aninfinite variety of physical" dimensions.

Through the use of the sync inputs and outputs and the properpositioning of switch S4, FIGS. 1 and 2, one sound distribution systemcan be set up as the master and can be coupled to a plurality of slavesound distribution systems. It is to be understood that the masterslaverelationship refers only to the generation of switching signals and doesnot refer to the sound input that is to be distributed among theplurality of speakers. Thus, referring to FIG. 6, a master sounddistribution system 160 is coupled by connector 165 to a slave sounddistribution system 161. Sound distribution system 161, in turn, iscoupled through the sync output terminal thereof, by connector 167, to asecond slave sound distribution system 162. The embodiment of theinvention described above utilizes four outputs, and thus the samenumerical output terminal from each of the sound distribution systems iscoupled to the same channel in a multichannel mixer 175. Each channel ofmixer 175 provides a corresponding output. Each output can be fed to anamplifier, such as amplifier 176 for channel A, amplifier 177 forchannel B, amplifier 178 for channel C and amplifier 179 for channel Dor can be taken from an amplifier as indicated by taps 190. Eachamplifier is connected to a corresponding speaker, such as speakers 182,183, 184 and 185.

By appropriately intercoupling a number of sound distribution systems,each having a sound input'representing, for example, one plane of sound,one channel of a multioral recording, a different instument in anorchestra playing the same music and/or different musical tunes andcoupling these sound distribution systems through a mixer, such as mixer175, an infinite number of variations can be produced in the total soundeffect sensed by a listener located with in the listening area.

The values for the components shown in FIG. 2 are given hereinbelow:

Component Value Component Value R1 510 C-l lKuf Electrolytic R2 270 KC-2 500 uf do. R3 750 G3 250 uf do. R4 100 K C-4 10 uf do. R5 47 K C-5uf do. R6 47 K C-6 10 uf do. R7 1K C147 10 uf do. R8 10 C-8 25 uf do. R922 K C-1 1 .22 Paper Rl0 1 l M LIN C-12 .22 do. RIOB I M LIN C-13 .22do. R11 750 C-1 4 .22 do. R12 330 K C-21 .22 do. R13 330 K C-22 .22 do.R14 1 K C-23 .22 do. R15 500 C24 .22 do. R16 750 C3] 1 uf ElectrolyticR17 2 K LIN C-32 luf do.

-Contmued Component Value Component Value R18 7.5 K C-33 1 uf do. R197.5 K C-34 l uf do. R20 1.5 M C-4l 1 uf R21 47 K 0-42 1 uf R22 47 K C-43l uf R23 47 K C-44 l uf R24 47 K C-51 .02 Ceramic R25 100 K C- 52 .02do. R26 12 C-53 .02 do. R27 1.2 K C54 .02 do. R28 100 K C-55 .02 do. R29K C-56 .001 R30 C-61 .47 Paper R31 50 K C-62 .47 do. R32 50 K C-63 .47do. R33 50 K C-64 .47 do. R34 50 K Tl 2N5l63 R35 25K T2 2N5163 R36 68 MT3 2N2400 R41 6.8 K T4 2N4105 R42 6.8 K T5 2N3904 R43 6,8 K To 2N3904R44 6.8 K T7 2N3904 R50 T8 2SC485 R51 1.5 M T9 R52 1.5 M T10 2N4105 R531.5 M T1 1 do. R54 1.5 M T12 do. R60 200 K LIN T13 do. R61 K T14 do.

51 SPST S2 SPDT S3 SPDT S4 SPDT RPl A-509-032976 Sprague R1 2 do. RP3do. RP4 do. J1 High Impedance Input Phone Jack .12 Low Impedance InputPhone Jack J3 Pedal, 3 Conductor .14 Sync Out RCA .15 Sync In RCA J6Scanner Indication J7 Tape in RCA J8 Aux. Input/Output RCA JA Channel.A" Output RCA .18 Channel 8" Output RCA .IC Channel C" Output RCA JDChannel D" Output RCA TRl VAC to 12.6 VAC.5A B1 NE2 LAS B2 ZOQFilamentT15 2N4105 T16 do. T17 do. T21 2N3904 T22 do. T23 do. T24 do. T31 2N5462T32 do. T33 do. T34 do. D1 1 ET3 D2 1 ET3 Although the invention hasbeen described in detail with respect to exemplary embodiments thereof,it will be understood by those of ordinary skill in the art thatvariations and modifications may be effected within the scope and spiritof the invention.

I claim:

1. A sound distribution system for cyclically distributing soundradiation in a plurality of different directions comprising:

a plurality of speakers located so as to define the perimeter of alistening area;

an input for receiving an electrical input signal corresponding to asound signal;

means for connecting said input in parallel with said plurality ofspeakers;

a plurality of switch means, individual to said speakers, forselectively actuating a corresponding said speaker responsive to aswitching control signal;

means connected to said switch means for generating a plurality oftrains of said switching control signals, equal in number to the numberof said speakers, which differ in phase such that the switching controlsignals from the individual trains are presented sequentially toindividual of said switch means so that said switch means are cyclicallyactuated to cause sequential actuating of said speakers and henceproduce a cyclical distribution of sound radiation from said pluralityof speakers; and

control means individual to said switch means and coupled to saidgenerating means for selectively coupling one of said trains ofswitching signals to a corresponding said switch means, said controlmeans being operably responsive to switching signals from a further ofsaid trains of switching signals generated by said generating means.

2. A sound distribution system in accordance with claim 1 and furtherincluding preventing means connected in series between each said inputand the corresponding said speaker for preventing the grounding of thecorresponding said speaker upon the grounding of any other said speaker;and wherein each said switch means comprises a field effect transistorelectrically connected in parallel across said speaker, said fieldeffect transistor having a source electrically connected between saidpreventing means and said speaker, a drain electrically connected toground and a gate for receiving a corresponding said switching controlsignal, said field effect transistor, when conducting thereby groundingsaid speaker.

3. A sound distribution system in accordance with claim 1 wherein saidswitching control signals are substantially square waves and saidswitching control signal generating means comprises:

pulse responsive means responsive to a train of pulses applied theretofor sequentially generating first and second subtrains of pulses fromalternate pulses in said train; and

square wave generating means-responsive to said subtrains of pulses forgenerating said plurality of trains of switching signals.

4. A sound distribution system in accordance with claim 3 wherein saidswitching control signal generating means further comprises oscillatormeans connectable to the input of said pulse responsive means forgenerating a train of timed pulses, said oscillator means comprising avariable frequency oscillator which is adjustable to provide a variablecycle frequency.

5. A sound distribution system in accordance with claim 4 which iscompletely electronic and further comprising means for continuouslyvarying the output frequency of said variable frequency oscillator.

6. A sound distribution system in accordance with claim 3 wherein saidswitching signal generating means further comprises a frequency dividingmeans for dividing the frequency of said train of timed pulses in halfsuch that one pulse is generated for every two pulses in said train oftimed pulses, and means for selectively connecting said dividing meansbetween said oscillator and said signal generating means.

7. A sound distribution system in accordance with claim 3 wherein eachsaid control means comprises an electronic switch having a conductingand nonconducting state for, in the conducting state, selectivelycoupling said one signal train to said corresponding switch means, eachsaid electronic switch being turned on by the leading edge of theswitching signal signal in said further signal train, said furthersignal train containing the next switching control signal in sequence soas to provide a phase delay in the switching signal equal to the phasedifference between successive signal trains.

8. A sound distribution system in accordance with claim 7 and furthercomprising wave shaping means for rounding off the leading and trailingedges of said phase delayed square waves thereby permitting a gradualoperation of each of said switch means and consequently a gradualactuation of the corresponding said speaker.

9. An electronic system for cyclically distributing a sound input signalto a plurality of outputs, said system comprising:

an input for receiving the sound input signal;

a plurality of output terminals;

means for connecting said sound receiving input in parallel to each ofsaid output terminals, including means for preventing the grounding ofeach output terminal upon the grounding of any other said outputterminal;

a plurality of switch means individual to said output terminals, eachswitch means connected in parallel across said output terminal andbetween said preventing means and said output terminals for normallygrounding said terminal and, in response to a switching control signal,for undergrounding said terminal; and

means connected to said switch means for generating a plurality oftrains of said switching control signals, equal in number to the numberof said output terminals which differ in phase such that the switchingcontrol signals from the individual trains are presented sequentially toindividual of said switch means so that said switch means are cyclicallyactuated to cause sequential undergrounding of said output terminals.

10. An electronic system in accordance with claim 9 wherein each saidswitch means comprises a field effect transistor electrically connectedin parallel across said output terminal, said field effect transistorhaving a source electrically connected between said preventing means andsaid output terminal, a drain electrically connected to ground and agate for receiving a corresponding said switching control signal, saidfield effect transistor when conducting thereby grounding said outputterminal and, when actuated in response to said switching controlsignal, ungrounding said output terminal. I

11. An electronic system in accordance with claim 9 wherein saidswitching control signals are substantially square waves and saidswitching control signal generating means comprises:

pulse responsive means responsive to a train of pulses applied theretofor sequentially generating first and second subtrains of pulses fromalternate pulses in said train;.and

square wave generating means responsive to said subtrains of pulses forgenerating said plurality of trains of switching signals.

12. An electronic system in accordance with claim 11 wherein saidswitching control signal generating means further comprises oscillatormeans connectable to the input of said pulse responsive means forgenerating a train of timed pulses, said oscillator means comprising avariable frequency oscillator which is adjustable to provide a variablecycle frequency.

13. An electronic system in accordance with claim 12 which is completelyelectronic and further comprising means for continuously varying theoutput frequency of said variable frequency oscillator.

14. An electronic system in accordance with claim 11 wherein saidswitching signal generating means further comprises frequency dividingmeans for dividing the frequency of said train of timed pulses in halfsuch that one pulse is generated for every two pulses in said train oftimed pulses, and means for selectively connecting said dividing meansbetween said oscillator and said signal generating means.

15. An electronic system in accordance with claim 11 wherein each saidcontrol means comprises an electronic switch having a conducting andnon-conducting state for, in the conducting state, selectively couplingsaid one. signal train to said corresponding switch means, each saidelectronic switch being turned on by the leading edge of the switchingsignal signal in said further signal train, said further signal traincontaining the next switching control signal in sequence so as toprovide a phase delay in the switching signal equal to the phasedifference between successive signal trains.

16. An electronic system in accordance with claim 15 further comprisingwave shaping means for rounding off the leading and trailing edges ofsaid phase delayed square waves thereby permitting a gradual operationof each of said switch means and consequently a gradual grounding of thesaid corresponding speaker.

17. An electronic apparatus for cyclically distributing a plurality ofsound input signals to a plurality of sound outputs, said apparatuscomprising:

a plurality of sound distributions devices, each sound distributiondevice comprising:

means for receiving a sound input signal;

a plurality of sound output terminals;

first means for connecting said sound input means in parallel to each ofsaid sound output terminals, including means for preventing thegrounding of each sound output terminal when any other sound outputterminal is grounded;

a plurality of signal responsive switch means equal in number to thenumber of said output terminals and connected in parallel between saidpreventing means and said sound output terminal, for normally groundinga corresponding output terminal, each switch means responsive to asignal for undergrounding a corresponding said sound output terminal;means for generating a plurality of trains of switching signalsdiffering in phase, whereby the generation of a first signal to thegeneration of a second signal within any signal train defines a cycleand the signal trains are generated such that the switching signals fromthe individual signal trains are presented sequentially within one cycleto a corresponding said switch means, the number of signal trains beingequal to the number of sound output terminals; and

second means for connecting each said switching signal generating meansto said corresponding switch means such that said switching signalssequentially actuate said corresponding switch means thereby producingthe cyclic distribution of the sound input signal to said plurality ofsound output terminals;

said apparatus further comprising a mixer means for mixing a pluralityof sound input signals and for providing a plurality of sound outputsignals, said mixer means comprising a plurality of channels wherebyeach channel mixes a plurality of input signals and provides one outputchannel; and

further means for connecting at least one of said sound output terminalsof each said sound distribution device to the same one of said channelsin said mixer means.

18. An electronic apparatus in accordance with claim 17 wherein eachsaid sound distribution device further comprises means for synchronizingthe generation of said plurality of signal trains with the generation ofsaid plurality of signal trains of at least one other sound distributiondevice, said further connecting means comprises a plurality of sets ofconductors, each conductor set connecting a corresponding said sounddistribution device to said mixer means such that each sound outputterminal corresponding to the same phase signal train is connected tothe same one of said channels of said mixer means.

1. A sound distribution system for cyclically distributing soundradiation in a plurality of different directions comprising: a pluralityof speakers located so as to define the perimeter of a listening area;an input for receiving an electrical input signal corresponding to asound signal; means for connecting said input in parallel with saidplurality of speakers; a plurality of switch means, individual to saidspeakers, for selectively actuating a corresponding said speakerresponsive to a switching control signal; means connected to said switchmeans for generating a plurality of trains of said switching controlsignals, equal in number to the number of said speakers, which differ inphase such that the switching control signals from the individual trainsare presented sequentially to individUal of said switch means so thatsaid switch means are cyclically actuated to cause sequential actuatingof said speakers and hence produce a cyclical distribution of soundradiation from said plurality of speakers; and control means individualto said switch means and coupled to said generating means forselectively coupling one of said trains of switching signals to acorresponding said switch means, said control means being operablyresponsive to switching signals from a further of said trains ofswitching signals generated by said generating means.
 2. A sounddistribution system in accordance with claim 1 and further includingpreventing means connected in series between each said input and thecorresponding said speaker for preventing the grounding of thecorresponding said speaker upon the grounding of any other said speaker;and wherein each said switch means comprises a field effect transistorelectrically connected in parallel across said speaker, said fieldeffect transistor having a source electrically connected between saidpreventing means and said speaker, a drain electrically connected toground and a gate for receiving a corresponding said switching controlsignal, said field effect transistor, when conducting thereby groundingsaid speaker.
 3. A sound distribution system in accordance with claim 1wherein said switching control signals are substantially square wavesand said switching control signal generating means comprises: pulseresponsive means responsive to a train of pulses applied thereto forsequentially generating first and second subtrains of pulses fromalternate pulses in said train; and square wave generating meansresponsive to said subtrains of pulses for generating said plurality oftrains of switching signals.
 4. A sound distribution system inaccordance with claim 3 wherein said switching control signal generatingmeans further comprises oscillator means connectable to the input ofsaid pulse responsive means for generating a train of timed pulses, saidoscillator means comprising a variable frequency oscillator which isadjustable to provide a variable cycle frequency.
 5. A sounddistribution system in accordance with claim 4 which is completelyelectronic and further comprising means for continuously varying theoutput frequency of said variable frequency oscillator.
 6. A sounddistribution system in accordance with claim 3 wherein said switchingsignal generating means further comprises a frequency dividing means fordividing the frequency of said train of timed pulses in half such thatone pulse is generated for every two pulses in said train of timedpulses, and means for selectively connecting said dividing means betweensaid oscillator and said signal generating means.
 7. A sounddistribution system in accordance with claim 3 wherein each said controlmeans comprises an electronic switch having a conducting andnon-conducting state for, in the conducting state, selectively couplingsaid one signal train to said corresponding switch means, each saidelectronic switch being turned on by the leading edge of the switchingsignal signal in said further signal train, said further signal traincontaining the next switching control signal in sequence so as toprovide a phase delay in the switching signal equal to the phasedifference between successive signal trains.
 8. A sound distributionsystem in accordance with claim 7 and further comprising wave shapingmeans for rounding off the leading and trailing edges of said phasedelayed square waves thereby permitting a gradual operation of each ofsaid switch means and consequently a gradual actuation of thecorresponding said speaker.
 9. An electronic system for cyclicallydistributing a sound input signal to a plurality of outputs, said systemcomprising: an input for receiving the sound input signal; a pluralityof output terminals; means for connecting said sound receiving input inparallel to each of said oUtput terminals, including means forpreventing the grounding of each output terminal upon the grounding ofany other said output terminal; a plurality of switch means individualto said output terminals, each switch means connected in parallel acrosssaid output terminal and between said preventing means and said outputterminals for normally grounding said terminal and, in response to aswitching control signal for undergrounding said terminal; and meansconnected to said switch means for generating a plurality of trains ofsaid switching control signals, equal in number to the number of saidoutput terminals which differ in phase such that the switching controlsignals from the individual trains are presented sequentially toindividual of said switch means so that said switch means are cyclicallyactuated to cause sequential undergrounding of said output terminals.10. An electronic system in accordance with claim 9 wherein each saidswitch means comprises a field effect transistor electrically connectedin parallel across said output terminal, said field effect transistorhaving a source electrically connected between said preventing means andsaid output terminal, a drain electrically connected to ground and agate for receiving a corresponding said switching control signal, saidfield effect transistor when conducting thereby grounding said outputterminal and, when actuated in response to said switching controlsignal, ungrounding said output terminal.
 11. An electronic system inaccordance with claim 9 wherein said switching control signals aresubstantially square waves and said switching control signal generatingmeans comprises: pulse responsive means responsive to a train of pulsesapplied thereto for sequentially generating first and second subtrainsof pulses from alternate pulses in said train; and square wavegenerating means responsive to said subtrains of pulses for generatingsaid plurality of trains of switching signals.
 12. An electronic systemin accordance with claim 11 wherein said switching control signalgenerating means further comprises oscillator means connectable to theinput of said pulse responsive means for generating a train of timedpulses, said oscillator means comprising a variable frequency oscillatorwhich is adjustable to provide a variable cycle frequency.
 13. Anelectronic system in accordance with claim 12 which is completelyelectronic and further comprising means for continuously varying theoutput frequency of said variable frequency oscillator.
 14. Anelectronic system in accordance with claim 11 wherein said switchingsignal generating means further comprises frequency dividing means fordividing the frequency of said train of timed pulses in half such thatone pulse is generated for every two pulses in said train of timedpulses, and means for selectively connecting said dividing means betweensaid oscillator and said signal generating means.
 15. An electronicsystem in accordance with claim 11 wherein each said control meanscomprises an electronic switch having a conducting and non-conductingstate for, in the conducting state, selectively coupling said one signaltrain to said corresponding switch means, each said electronic switchbeing turned on by the leading edge of the switching signal signal insaid further signal train, said further signal train containing the nextswitching control signal in sequence so as to provide a phase delay inthe switching signal equal to the phase difference between successivesignal trains.
 16. An electronic system in accordance with claim 15further comprising wave shaping means for rounding off the leading andtrailing edges of said phase delayed square waves thereby permitting agradual operation of each of said switch means and consequently agradual grounding of the said corresponding speaker.
 17. An electronicapparatus for cyclically distributing a plurality of sound input signalsto a plurality of sound outputs, said Apparatus comprising: a pluralityof sound distributions devices, each sound distribution devicecomprising: means for receiving a sound input signal; a plurality ofsound output terminals; first means for connecting said sound inputmeans in parallel to each of said sound output terminals, includingmeans for preventing the grounding of each sound output terminal whenany other sound output terminal is grounded; a plurality of signalresponsive switch means equal in number to the number of said outputterminals and connected in parallel between said preventing means andsaid sound output terminal, for normally grounding a correspondingoutput terminal, each switch means responsive to a signal forundergrounding a corresponding said sound output terminal; means forgenerating a plurality of trains of switching signals differing inphase, whereby the generation of a first signal to the generation of asecond signal within any signal train defines a cycle and the signaltrains are generated such that the switching signals from the individualsignal trains are presented sequentially within one cycle to acorresponding said switch means, the number of signal trains being equalto the number of sound output terminals; and second means for connectingeach said switching signal generating means to said corresponding switchmeans such that said switching signals sequentially actuate saidcorresponding switch means thereby producing the cyclic distribution ofthe sound input signal to said plurality of sound output terminals; saidapparatus further comprising a mixer means for mixing a plurality ofsound input signals and for providing a plurality of sound outputsignals, said mixer means comprising a plurality of channels wherebyeach channel mixes a plurality of input signals and provides one outputchannel; and further means for connecting at least one of said soundoutput terminals of each said sound distribution device to the same oneof said channels in said mixer means.
 18. An electronic apparatus inaccordance with claim 17 wherein each said sound distribution devicefurther comprises means for synchronizing the generation of saidplurality of signal trains with the generation of said plurality ofsignal trains of at least one other sound distribution device, saidfurther connecting means comprises a plurality of sets of conductors,each conductor set connecting a corresponding said sound distributiondevice to said mixer means such that each sound output terminalcorresponding to the same phase signal train is connected to the sameone of said channels of said mixer means.